1. Field of the Art
The present invention relates generally to a resilient bushing which is disposed between two members in a vibration system, for resiliently connecting the two members so as to damp vibrations in the system, and more particularly to such resilient bushing of generally cylindrical shape which comprises an inner and an outer sleeve, and a cylindrical resilient member interposed between the inner and outer sleeves.
2. Related Art Statement
In the art of absorbing or damping vibrations between two members, a resilient bushing is known, which generally includes an inner metal sleeve, an outer metal sleeve disposed around the inner metal sleeve in co-axial and radially-spaced relation with each other, and a cylindrical resilient or rubber member interposed between the inner and outer metal sleeves. Various types of such cylindrical resilient bushings have been proposed and used for meeting different requirements depending upon specific environments in which the bushings are used.
For example, the above-indicated cylindrical resilient bushings are used as arm bushings which pivotally couple suspension arms to a suspension member in an independent suspension system of trailing arm-type in an automotive vehicle. The resilient bushings for this application are required, on the one hand, to exhibit relatively hard spring characteristics in their radial direction, for assuring high driving stability of the vehicle. For improving the driving comfort of the vehicle, on the other hand, the resilient bushings are required to exhibit relatively soft spring characteristics in their circumferential direction, i.e., in the direction of twisting about their axis, in order to prevent deterioration of vibration-damping ability of coil springs supporting the vehicle. For enhanced cornering stability of the vehicle, the bushings are further required to exhibit axial spring characteristics wherein the rate of increase in deflection or strain of the resilient member as a load applied thereto is increased, is reduced at a relatively low level of the load, up to which level the rate of increase in the deflection is relatively high.